Method of treating fibrous material



ug- 18, 1935- J. M. HoTHERsALL 2,051,047

METHOD OF TREATING FIBROUS MATERIAL Filed June 25, 1953 INVENTOR JA l. www

ATTORNEYS Patented Aug. 18, 1936 UNITED STATES PATENT OFFICE METHOD 0F TREATING FIBROUS MATERIAL Application June 23, 1933, Serial No. 677,330

2 Claims.

The present invention relates in the main to treating fibrous sheet material to render sections more or less transparent, and while it has more particular reference to the creation of windows for containers such as are used for the packaging of milk and similar liquids, it will be apparent that its several features have other valuable applications and uses.

The invention has for its object broadly the transforming of portions of a fibrous sheet, which is more or less opaque, into transparent or translucent sections, this transformation being the result of a thinning of the fibrous wall by pressure together with the simultaneous forcing of a penetrating liquid such as oil, glycerin or the like into the thinned areas.

The invention also contemplates the forming of windows for the walls of milk or other liquid containers so that the cream line may be discernible through the window.

One object of the invention, therefore, is the making of such transparent sections in the blank sheet which is subsequently formed into and treated for such liquid containers.

To heighten the effect of observation through such windows the invention also contemplates the formation of a composite window in a fibrous sheet wherein transparent thinned areas in each window are separated and set oi by intermediate opaque and unthinned sections, the application of the thinning pressures and the application of the penetrating liquid for forming the window sections being a matter of location within the sheet wall, these intermediate opaque sections contrasting with the thinned surfaces and aiding in observance of substances through the window by reason of this contrast. This is particularly noticeable in viewing, through such a composite window, such substances as milk on which the cream appears.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which, taken in connection with the accompanying drawing, discloses a preferred embodiment thereof.

Referring to the drawing:

Figure 1 is a perspective view of a container which has been provided with transparent windows produced according to the method steps of the present invention;

Fig. 2 is a schematic cross section through a pressure member shown in position above the sheet of fibrous material, the view also illustrating application of a penetrating liquid to the pressure surfaces of the pressure member;

Fig. 3 is a view similar to Fig. 2 but illustrating the use of a pair of cooperating pressure members in the closed or pressure position in the sheet thinning and liquid impregnating operations; and 5 Fig. 4 is a schematic view illustrating the step of moisture proofing a windowed container made from a sheet of fibrous material.

The drawing in addition to showing method steps for producing transparent or translucent 10 window sections in a sheet of brous material according to the present invention also discloses a fully formed liquid container with such transparent sections.

In producing such a windowed container a 15 sheet of brous material II is provided as the blank from which such a container is subsequently formed.

The sheet blank II may first be placed upon a flat table I2 and beneath a pressure die member 20 I3. This die is shown as adapted to produce a composite window and is preferably formed on its lower face with projecting parts I4 which are set oil' by transverse grooves I5, the lower face 0f the parts I4 being the required size and shape 25 desired in the window panels to be produced. A flat, ungrooved die member would be used for a single or simple window.

A suitable penetrating liquid such as oil or glycerin is preferably next applied to the lower 30 surface of the projecting parts I4 in any suitable manner as by means of a roller I6 as illustrated in Fig. 2.

'Ihe sheet blank II is then engaged by the die member I3 which is moved downwardly as the 35 blank rests upon the table I2. In this movement the projecting surfaces I4 are pressed into the upper surface of the sheet and the latter is compressed and thinned in those sections of the sheet which are engaged between the parts I4 and the 40 table, the intermediate grooves I5 giving freedom from pressure as to those parts of the blank at that place.

Instead of placing the blank I I on a flat surface after the penetrating liquid is applied to the lower face of the pressure member I3 such as sheet may be positioned between a pair of cooperating pressure members which clamp on it from top and bottom as illustrated in Fig. 3. In this case the lower pressure member I8 is provided with pro- 50 jections I9 formed on its upper face and in vertical alignment with the projections I4 of the member I3. The upper face of the member I8 will match the face of member I3 and for the compositc construction shown will also be formed with grooves 2l which set oi! the projecting surfaces.

'Ihe penetrating liquid may be suitably applied to either one or both of the pressure faces of the members and these members are then brought closer together with the blank il clamped between as shown. The thinned sections of the sheet or blank in this case are located along the horizontal center, both surfaces of the blank being pressed inwardly to provide the thinned sections. .Y

'I'he thinned blank Il may then be suitably shaped or formed and glued in the usual manner to produce a container or box 23 having side walls 3| (Fig. 1) the thinned section being located adjacent a top end 32 the other end having a suitable bottom 33. 'Ihe composite window in a side wall 3| of the container and produced by the thinning and liquid penetrating step described is composed of transparent panels 34 between which unthinned opaque mullions 35 set oil and separate the window panels.

These mullions 35 being of the same thickness as the rest of the wall 3i and also being untreated present the same opaque surface as the rest of the container wall and give a better visual effect to substances viewed through the windows. Where the container is a liquid container holding, for example, milk, the cream line (designated by the numeral 36) appears more distinct by reason of this contrast of surfaces.

Where the container 29 is used for liquids it may be suitably treated with a moisture-proofing material such as paraillne and this may be applied both inside and outside if desired. The parailine may be sprayed on the container before 'closing of its top end 32, or it may be dipped in paramne if desired as illustrated in Fig. 4. In this ligure there is schematically shown a bath 3l of liquid paramne or similar material contained in some suitable holding vessel or tank 33. A container 29 dipped in such a bath so that it is first filled with the paramne which is then emptied and drained back, will be suitably moisture-proofed both inside and outside.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the steps of the process described and their order of accomplishment without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the process hereinbefore described being merely a preferred embodiment thereof.

I claim:

1. A closed liquid proof container for milk and the like, said container including side and end walls formed ci.' substantially opaque fibrous sheet 20 material, a side wall of said container having a thinned compressed portion near its top impregnated with a penetrating liquid to form a translucent window in said wall, whereby the cream line of the milk conned within said opaque container is visible through said windows, the inner and outer surfaces of the container including the thinned portions being coated with paraffin.

2. In the method of making a container having translucent liquid proof windows, the steps which Y comprise thinning a container having side and end walls to form said windows, impregnating the thinned portion with a penetrating liquid to decrease the opacity of such windows, and then coating the inner and outer surfaces of the container including the thinned portions with paraffin.

JOHN M. HOTHERSAIJ... 

